fix innodb_metrics for mariadb 10.5+ (fixes #494) (#523)

* determine column name for innodb_metrics before
querying
adds support more mariadb 10.4+, fixes 494

Signed-off-by: Mike <maemigh@gmail.com>

CHANGELOG.md

@@ -15,6 +15,7 @@
 * [FEATURE] Add collector for `performance_schema.memory_summary_global_by_event_name` (PR #515) #75
 * [BUGFIX] Fixed output value of wsrep_cluster_status #473
 * [BUGFIX] Fix collect.info_schema.innodb_tablespaces for new table names #516
+* [BUGFIX] Fix collect.info_schema.innodb_metrics for new field names (mariadb 10.5+) #494
 
 ### BREAKING CHANGES:
 

collector/info_schema_innodb_metrics.go

@@ -18,6 +18,8 @@ package collector
 import (
 	"context"
 	"database/sql"
+	"errors"
+	"fmt"
 	"regexp"
 
 	"github.com/go-kit/kit/log"
@@ -25,13 +27,20 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 )
 
+const infoSchemaInnodbMetricsEnabledColumnQuery = `
+	SELECT
+	    column_name
+	  FROM information_schema.columns
+	  WHERE table_name = 'INNODB_METRICS'
+	    AND column_name IN ('status', 'enabled')
+	`
+
 const infoSchemaInnodbMetricsQuery = `
 		SELECT
 		  name, subsystem, type, comment,
 		  count
 		  FROM information_schema.innodb_metrics
-		  WHERE status = 'enabled'
+		  WHERE ` + "`%s` = '%s'"
-		`
 
 // Metrics descriptors.
 var (
@@ -83,7 +92,24 @@ func (ScrapeInnodbMetrics) Version() float64 {
 
 // Scrape collects data from database connection and sends it over channel as prometheus metric.
 func (ScrapeInnodbMetrics) Scrape(ctx context.Context, db *sql.DB, ch chan<- prometheus.Metric, logger log.Logger) error {
-	innodbMetricsRows, err := db.QueryContext(ctx, infoSchemaInnodbMetricsQuery)
+	var enabledColumnName string
+	var query string
+
+	err := db.QueryRowContext(ctx, infoSchemaInnodbMetricsEnabledColumnQuery).Scan(&enabledColumnName)
+	if err != nil {
+		return err
+	}
+
+	switch enabledColumnName {
+	case "STATUS":
+		query = fmt.Sprintf(infoSchemaInnodbMetricsQuery, "status", "enabled")
+	case "ENABLED":
+		query = fmt.Sprintf(infoSchemaInnodbMetricsQuery, "enabled", "1")
+	default:
+		return errors.New("Couldn't find column STATUS or ENABLED in innodb_metrics table.")
+	}
+
+	innodbMetricsRows, err := db.QueryContext(ctx, query)
 	if err != nil {
 		return err
 	}

collector/info_schema_innodb_metrics_test.go

@@ -15,6 +15,7 @@ package collector
 
 import (
 	"context"
+	"fmt"
 	"testing"
 
 	"github.com/DATA-DOG/go-sqlmock"
@@ -31,8 +32,13 @@ func TestScrapeInnodbMetrics(t *testing.T) {
 	}
 	defer db.Close()
 
+	enabledColumnName := []string{"COLUMN_NAME"}
+	rows := sqlmock.NewRows(enabledColumnName).
+		AddRow("STATUS")
+	mock.ExpectQuery(sanitizeQuery(infoSchemaInnodbMetricsEnabledColumnQuery)).WillReturnRows(rows)
+
 	columns := []string{"name", "subsystem", "type", "comment", "count"}
-	rows := sqlmock.NewRows(columns).
+	rows = sqlmock.NewRows(columns).
 		AddRow("lock_timeouts", "lock", "counter", "Number of lock timeouts", 0).
 		AddRow("buffer_pool_reads", "buffer", "status_counter", "Number of reads directly from disk (innodb_buffer_pool_reads)", 1).
 		AddRow("buffer_pool_size", "server", "value", "Server buffer pool size (all buffer pools) in bytes", 2).
@@ -42,7 +48,8 @@ func TestScrapeInnodbMetrics(t *testing.T) {
 		AddRow("buffer_pool_pages_data", "buffer", "gauge", "Number of data buffer pool pages", 6).
 		AddRow("buffer_pool_pages_total", "buffer", "gauge", "Number of total buffer pool pages", 7).
 		AddRow("NOPE", "buffer_page_io", "counter", "An invalid buffer_page_io metric", 999)
-	mock.ExpectQuery(sanitizeQuery(infoSchemaInnodbMetricsQuery)).WillReturnRows(rows)
+	query := fmt.Sprintf(infoSchemaInnodbMetricsQuery, "status", "enabled")
+	mock.ExpectQuery(sanitizeQuery(query)).WillReturnRows(rows)
 
 	ch := make(chan prometheus.Metric)
 	go func() {